Sure, but one thing is opinions, another is hard facts from numbers in the top rank of the game. Here is a similar screenshot from Solar Gold. Win rates look pretty solid to me :)

The overall win rate being low just means that there are a lot of players who don't understand how to make the most out of the winning strategies in Deception. In capable hands, Deception is as competitive as any other God. It is however not as easy and straightforward as a pure aggro deck, and perhaps that is the reason why in the aggregate the win rate drops so much.